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Fluid-Structure Interaction between Structural Components of Hydraulic Turbine and Fluid Flow
Havlásek, Michal ; Malenovský, Eduard (oponent) ; Vimmr, Jan (oponent) ; Pochylý, František (vedoucí práce)
This doctoral thesis deals with two cases of fluid-structure interaction (FSI). The concern of the first part is to investigate the mutual interaction between the rotor of rotating machinery and fluid within the annular seals. The effect of the annular seals on the dynamic behaviour of the whole machine is described by the rotordynamic coefficients. The current models for the determination of the rotordynamic coefficients of the annular seal use many simplifications. This thesis presents five different analyses of rotordynamic coefficients of the plain annular seal of the oxidizer pump. Each of those five analyses uses a different level of simplification. The most simple analysis models only the volume of fluid within the annular seal. And the most sophisticated analysis models fluid flow within the entire pump with the eccentric rotor. The second part of this thesis defines a new method for the solution of interaction between the fluid and flexible body. This method is based on the solution of the inverse vibration problem. The direct vibration problem, which is as well known as the eigenvalue problem, uses the mass, damping and stiffness matrices, which are collectively called ''the structural matrices'', and determines in the most general case the Jordan matrix and modal matrices of right and left eigenvectors. The inverse vibration problem is used for the definition of the structural matrices based on the Jordan matrix and modal matrices of right and left eigenvectors. The inverse vibration problems can be divided into two types. If all eigenvalues and eigenvectors are known, then it is called the full problem. On contrary, if at least one mode of vibration is unknown, then it is called the partial problem. Five algorithms for the solution of the inverse vibration problem are defined in this thesis. However, two of these five algorithms are versatile, each one for one type of inverse vibration problem. The algorithm for the solution of the full problems was presented in 1979 by Otakar Daněk. The algorithms for the solution of the partial problem, which are presented in this thesis, are the very first algorithms for the solution of this type of inverse vibration problem. And the versatile algorithm for partial problems is called the algorithm for the partial problems with the selection of additional eigenvalues. The application of these two algorithms for the solution of the inverse vibration problem for the full problems and the partial problems are demonstrated on the solution of two cases of interaction between the fluid and flexible body.
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Ověření vlivu geometrie na dynamické vlastnosti ponořeného tělesa
Černý, Tomáš ; Pochylý, František (oponent) ; Habán, Vladimír (vedoucí práce)
Ponořením tělesa do kapaliny vznikají přídavné účinky, se kterými je nutno počítat při návrhu strojů. Přídavné účinky od kapaliny mají vliv na dynamické vlastnosti tělesa. V této práci je vyšetřován pokles vlastních frekvencí a nárůst poměrného útlumu při postupném ponořování tělesa do kapaliny. Diplomová práce je založena na experimentu, který je proveden na sérii součástí ploché pásové oceli různých šířek. Vyšetřeny jsou první tři ohybové a první tři torzní tvary kmitu volně zavěšené součásti. Důraz je kladen na vliv šířky součásti. V další fázi experimentu je vyšetřen vliv blízkosti pevné stěny na dynamické vlastnosti vetknutého tělesa. Dále je provedeno určení přídavné hustoty od kapaliny pomocí modální analýzy s využitím softwaru ANSYS.
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Fluid-Structure Interaction between Structural Components of Hydraulic Turbine and Fluid Flow
Havlásek, Michal ; Malenovský, Eduard (oponent) ; Vimmr, Jan (oponent) ; Pochylý, František (vedoucí práce)
This doctoral thesis deals with two cases of fluid-structure interaction (FSI). The concern of the first part is to investigate the mutual interaction between the rotor of rotating machinery and fluid within the annular seals. The effect of the annular seals on the dynamic behaviour of the whole machine is described by the rotordynamic coefficients. The current models for the determination of the rotordynamic coefficients of the annular seal use many simplifications. This thesis presents five different analyses of rotordynamic coefficients of the plain annular seal of the oxidizer pump. Each of those five analyses uses a different level of simplification. The most simple analysis models only the volume of fluid within the annular seal. And the most sophisticated analysis models fluid flow within the entire pump with the eccentric rotor. The second part of this thesis defines a new method for the solution of interaction between the fluid and flexible body. This method is based on the solution of the inverse vibration problem. The direct vibration problem, which is as well known as the eigenvalue problem, uses the mass, damping and stiffness matrices, which are collectively called ''the structural matrices'', and determines in the most general case the Jordan matrix and modal matrices of right and left eigenvectors. The inverse vibration problem is used for the definition of the structural matrices based on the Jordan matrix and modal matrices of right and left eigenvectors. The inverse vibration problems can be divided into two types. If all eigenvalues and eigenvectors are known, then it is called the full problem. On contrary, if at least one mode of vibration is unknown, then it is called the partial problem. Five algorithms for the solution of the inverse vibration problem are defined in this thesis. However, two of these five algorithms are versatile, each one for one type of inverse vibration problem. The algorithm for the solution of the full problems was presented in 1979 by Otakar Daněk. The algorithms for the solution of the partial problem, which are presented in this thesis, are the very first algorithms for the solution of this type of inverse vibration problem. And the versatile algorithm for partial problems is called the algorithm for the partial problems with the selection of additional eigenvalues. The application of these two algorithms for the solution of the inverse vibration problem for the full problems and the partial problems are demonstrated on the solution of two cases of interaction between the fluid and flexible body.
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Ověření vlivu geometrie na dynamické vlastnosti ponořeného tělesa
Černý, Tomáš ; Pochylý, František (oponent) ; Habán, Vladimír (vedoucí práce)
Ponořením tělesa do kapaliny vznikají přídavné účinky, se kterými je nutno počítat při návrhu strojů. Přídavné účinky od kapaliny mají vliv na dynamické vlastnosti tělesa. V této práci je vyšetřován pokles vlastních frekvencí a nárůst poměrného útlumu při postupném ponořování tělesa do kapaliny. Diplomová práce je založena na experimentu, který je proveden na sérii součástí ploché pásové oceli různých šířek. Vyšetřeny jsou první tři ohybové a první tři torzní tvary kmitu volně zavěšené součásti. Důraz je kladen na vliv šířky součásti. V další fázi experimentu je vyšetřen vliv blízkosti pevné stěny na dynamické vlastnosti vetknutého tělesa. Dále je provedeno určení přídavné hustoty od kapaliny pomocí modální analýzy s využitím softwaru ANSYS.
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